org.evolvis.tartools.backgroundjobs

Interface BackgroundJob<V>

Type Parameters:

V -

All Known Subinterfaces:

BackgroundJobWithProperties<V>

All Known Implementing Classes:

CompositeBackgroundJob, WeightedBackgroundJob

public interface BackgroundJob<V>

A unit of work that may be processed asynchronously. An instance of this class represents a potentially long-running task that may be scheduled and processed asynchronously by a BackgroundJobScheduler. This interface models the “inside” part of the contract that is to be fulfilled by the code implementing a particular job. To schedule a job, use BackgroundJobScheduler.schedule(BackgroundJob) or BackgroundJobScheduler.schedule(String, BackgroundJob). See also: BackgroundJobInfo, BackgroundJobScheduler, BackgroundJobStatus

Author:

lukas

Method Summary

Modifier and Type	Method and Description
String	getDescription() Describe the job.
V	work(BackgroundJobMonitor monitor) Execute the Job.

Method Detail

work

V work(BackgroundJobMonitor monitor)
throws Exception

Execute the Job. This method is typically called by some sort of scheduler. This method should never be called twice on the same instance! While executing, implementations should use the BackgroundJobMonitor to communicate with the scheduler:

• Progress should be reported to the BackgroundJobMonitor through the BackgroundJobMonitor.announceTotal(int), BackgroundJobMonitor.reportProgressAbsolute(int) and BackgroundJobMonitor.reportProgressIncrement(int) methods.
• All logging should use the BackgroundJobMonitor.log(org.evolvis.tartools.backgroundjobs.BackgroundJobMonitor.Severity, Object) Method.
• Long-running operations should periodically poll the state of the BackgroundJobMonitor.isAborting() property, to check whether a cancellation was requested. If this is the case, this method should return as quickly as possible.
• Implementations can obtain a unique identifier for the current execution of this job using the BackgroundJobMonitor.getScheduledJobId() Method.

Parameters:

monitor - The job monitor that should be used to communicate with the scheduler.

Returns:

the result produced by this job. Schedulers should ignore the returned value if the job has been aborted before finishing normally.

Throws:

Exception - The scheduler should be prepared to deal with any kind of exception by marking the job as failed.

getDescription

String getDescription()

Describe the job.

Returns:

a human-readable Description of the job.